The negative affect from international break is when some players are return to their clubs with got injured so that's why some of European managers doesn't really like if their players playing with their national team and recently it just happend to Tottenham that confirmed their defender player Cristian Romero condition was not certain after defend Argentina national team and if Romero will not available this weekend i think this is big lost for Tottenham because so far his duet with Micky van de Ven was very strong to guarded Tottenham defensive lines and for every matches Romero always be performing well so if Romero not available when Tottenham playing against Fulham next weekend i think this will have any affect for Tottenham performance later
Though international breaks do affect a players performance but that doesn't mean that a player should not turn up for her country.
International break or not players are likely to be injured on pitch so that's why it is necessary for a coach to buy players that will be a replacement if injury occurs to their key players.
I believe that inasmuch as a players fitness is important to his team, we should also know that a player can't make his team alone as it requires team work and understanding to make a player visible on the pitch.
Though Cristian Romero defensive tactics with Micky Van De Ven has aided Tottenham hotspur in their campaign this season but I think a replacement like Eric dier can still help spurs against their match with Fulham